Dynamo-electric machine for the production of continuous and alternating currents.



J. SGHURGH. DYNAMO ELECTRIC MACHINE FOR THE PRODUCTION OF CONTINUOUS ANDALTERNATING OURRENTS.

APPLIOATION FILED MAY 15, 1908.

Patented Aug. 2, 1910.

5 SHEETS-SHEET l.

J. SGHU'ROH. DYNAMO ELEGTRIU MACHINE FOR THE PRODUCTION OF CONTINUOUSAND ALTERNATING OURRENTS.

u APPLICATION FILED MAY 15, 1908. 966,246a

5 SHEETSSHEET 2.

ll! Wj Patented Aug. .2, 191%.

J. SOHURGH DYNAMO ELECTRIC MACHINE FOR THE PRODUCTION OF CONTINUOUS ANDALTERNATING CURRBNTS.

APPLICATION FILED MAY 15, 1908.

Patented Aug. 2, 1910.

5 SHEETS-SHEET 3' ZQZZ 5 ii J. SGHURGH. DYNAMO ELECTRIC MACHINE FOR THEPRODUCTION OF CONTINUOUS AND ALTERNATIN G GURREN TS.

APPLICATION FILED MAY 16, 1908.

' s SHEETS-SHEET 4.

layi- Patented Aug. 2, 1910.

J. SCHURCH. DYNAMO ELECTRIC MACHINE FOR THE PRODUCTION OF CONTINUOUS ANDALTERNATING OURRENTS.

v I APPLIUATION FILED MAY 15 1908 9 24, Patented Au 2, 1910.

6 SHEETS-SHEET 5.

JAKOIB SCI-I'llRCI-I, OF BRUGHSAL, GERMANY.

DYNAMO-ELEOTRIC MACHINE FOR THE PRODUCTION OF CONTINUOUS AND ALTERNAT-ING CURRENTS.

Specification of Letters Patent Application filed May 15, 1908.

Patented Aug. 2, 1910. Serial No. 433,107.

To all whom it may concern.

Be it kIlOWfl that I, Janos SoHt'mon, a citizen'of the German Empire,residing at Bruchsal, inthe Grand Dukedom of Baden, Empire of Germany,have invented certain new and useful Improvements in Dynamo ElectricMachines for the Production of Continuous and Alternating Currents; andI do hereby declare the following to be a full, clear, and exactdescription of the illvention, such as will enable others skilled in theart to which it appertains to make and use the same.

The present invention relates to dynamo electric machines which servefor the production of continuous and alternating currents.

In spite of the essential advantages, namely the extraordinarily smallpercentage of energy used for their excitation, the

vknown kinds of machines having a single coil magnetic field systemwhether homopolar or heteropolar, have with few exceptions been employedonly for the production of alternating current and when used ascontinuous current machines are made almost entirely in the form ofmotors. The causes of this restricted use are various. Thus for examplethe obtaining of a sparkless current reversal presented difficulties inconsequence of the great alteration of the strength of field within theneutral zone on different current loads, as the distance between theedges of the poles could only be diminished up to a certain degree, andthe arrangement of reversing'poles for compensating for armaturereaction was impossible. Further. the surface of the armature in knownmachines was badly utilized, and the same had to be constructeddisproportionally large in order to attain a given output, so that'itwas naturally correspondingly heavy. The removal of these objectionsforms the main object of the present invention, the fundamental idea ofwhich is the formation of the poles of the machines as pole teeth'whichfit into one another and render possible at will a close approximationof the same to correspond to particular constructive requirementswhereby the interspace can nearly disappear. In these pole teeth theneverywhere only edges and no where parallel surfaces are opposed wherebymagnetic leakage as far as possible is counteracted. The utilization ofthe armature ment of the brushes being surface is consequently extremelyeifective so that as compared with known machines even of the mostcompact construction, in

proportion to the weight, a higher efficiency is attained, together witha not inconsiderable saving in copper and iron. The boundary line of thepole teeth can in this case be a suitable regular curve, if desired, ofthe form of curve of the graph of the electromotive force.

According to the present invention a form is selected for the boundaryline of the pole teeth, which permits of a continuous sparkless currentreversal even on strongly varying loads.

In the hitherto known machines without reversing poles a currentreversal without sparking could only be attained by the brushes beingactually displaced or ad justed. In contrast to these machines thepresent invention difiers by such a displacequite superfluous, acontinuous sparkless current reversal being attained without any suchadjustment. This is attained by the creation of a current reversal zoneof suitable width. For this purpose the course of the pole boundarylines regular in itself is interrupted in a suitable way correspondingto the action tobe obtained. Thus for instance the curves at suitableplaces could have pronounced breaks, that is to say, the curves bebroken in the form of steps. They would follow therefore the knownregular form as far as these abrupt breaks and then after these breaksagain resume their old direction. A spreading orexpansion of the currentreversal zone and thus sparkless running on varying load can also beattained by a subdivision of the pole surfaces. This subdivision can beconceived to be produced by the pole surfaces bounded by a continuouscurve being cut at regular intervals parallel to the armature conductorsand suitably spaced apart.

The invention is shown diagrammatically in the accompanying drawings,and also explained in several examples of forms of construction.

Figure 1, shows the armature winding diagram with the pole surfaces ofthe invention; Fig. 2 is a graphic representation of the method ofworking of the new machine; Fig. 3 shows a development of the polesurfaces of a 6-pole dynamo; and Fig.

4, an axial vertical section through the po casing of a dynamo machineof the present 1nvention; Figs. 5 to 9 lIlClllSlVG are similar views ofanother form of construction; Figs.

10 and 11 show the development and section of forms of construction ofmulti-coil. machines; Figs. 12 and 13 explain the construction of thearmature employed by me, and Fig. l t shows in section a machineprovided with an armature having spirally formed core disks.

The present invention relates to dynamo electric machines in which thepole rings a and b are provided with pole pieces 0 of novel form; Thecontours of the adjacent parts of the same can in this case be formed inany curve,'for instance for pole pieces which enter to a short distanceonly between each other (Figs. 3, l, 7 and 8) asinus like boundary maybe,employed, while for pole pieces engaging deeper into one another(Figs. 1, 5 and 9) a suitable triangular form of pole piece withstrongly rounded points is to be preferred in order to secure a uniformdistance apart of the edge or periphery of the pole pieces. The polepieces 0, preferably receive such a form that they diminish in thicknesstoward the outside that ,is to say run more or less to an edge as shownin Figs. 4, 8 and 11, so that these edges are constantly opposed to eachother in order to diminish magnetic leakage.

In machines in which the pole teeth 0, as represented in Figs. 1, 5, 9and 14, extend so deeply in between one another as seems preferable fromconsiderations of leakage, a decrease in sizeorsimplification of themachine, with a corresponding saving in material and weight, isobtained, and in such machines it is necessary in order to avoid certaineddy current losses to subdivide the whole armature d. In my machine inplace of the armature core disks being vertical to the armature axisk-which would necessi-' tate a field of unequal densityplates standingobliquely to the armature axis is or with a helical form (Figs. 12 and13) are chosen.

By forming the armature of separate helical sheets as shown in Figs. 12to 14 an excellent ventilation is furthermore obtained, so that thisarmature can, with an equal increase of temperature, be loadedconsiderably higher than in armatures in which the feature above setforth is absent. This is due to the fact that conical interspaces areformed between the separatesheets the greatest width of which spaces isproportional to the height and thickness of the armature core, disks.The armature disks therefore act as a ventilator whereby each separatedisk comes in contact with the air and thus an excellent cooling of the.armature results. In order now to obtain a current reversal zone as wideas possible, the-boundary line of the pole piece 0 according to thisinvention is given the form shown in Figs. 1 to 11.

In general the boundary lines or periphery m of the pole pieces 0 run inregular curves. At a suitable point, however, in the form ofconstruction shown in Figs. 1 to 4, they suddenly turn laterally for ashort distance, aiter which they again resume their former direction andform, or, as otherwise stated successive portions of the periphery ofthe pole pieces are olfset relatively to one 'another in the directionof rotation of the armature. In this manner are produced steps or breaksZ the boundary lines of which can be of any form and position.

As regards the method of working of the new pole teeth reference is madeto Fig. 2, in which thecurves I, I represent the boundary lines of theteeth and show at the same time the magnetic field of a pole when thearmature is without current. The curves II, I1 represent the cross fieldproduced by the armature winding when the excitation is switched 01f. Bytheaddition of the curves I and II or I and H the curves III and 111 areobtained, which represent the field 'actually present when the machineis under load. From these curves, somewhat distorted by .the reaction ofthe armature, can be ascertained the change in the number of lines offorce inclosed by a coil dueto the change in the angular position of thecoil. This change is separately shown for each pole by the curves IV and1V and it must be particularly pointed out that the apices of thesecurves, in consequence of the flat tening of the curves III and III -arealso flattened. By the addition of the curves IV and IV the inductioncurve V is obtained which also has flattened apices so that the derivedcurve VI of the electro-motive force in an armature coil due to changeofangular position is also deflected laterally on the passage throughthe zero position. In this way an expansion of the current reversal zoneis obtained. It is however advantageous that this deviating line shouldnot run quite horizontally. In order to interrupt the elcctro-motiveforce due to the self-induction of the coil short circuited by thebrushes, the shape and position of the steps Z are preferably arrangedin such a way that in this coil on passing the reversal zone anelectromotive force of equal strength but of opposite direction isinduced and thus a interspace p, no electromotive force (apartfrom thatdue to self-induction) is induced in the same, as neither an addition toor diminution of the number of lines of force takes place. The mode ofaction is exactly seen from the diagram (Fig. 6) significance of thevarious curves can be ob talned from the explanations of Fig. 2.

The form shown in Figs. to 11, as compared with that in Figs. 1 to 4,has the advantage that the total number of lines of force is diminishedcorresponding to the intervals p, while the action is in no way lessthan in the first described arrangement. The cross section of themagnetic circuit can therefore be diminished in the form shown in Figs.5 to 11 proportionally to the saving in lines of force, so that themachine is lighter. Furthermore the action of the cross field of thearmature will be lessened in a known manner by these savings.

In order to compensate for the electromotive force due to the selfinduction of the short-circuited coil, the grooves in the pole pieces inthe form shown in Fig. 9 terminate before reaching the bases of the polepieces whereby an approximately trapezoidal magnetic bridge is providedin each groove,

dimensions of which exactly suffice to inter-' rupt the electro-motiveforce due to selfinduction. The boundary lines of this triangular ortrapezoidal bridge will be determined empirically inpractice and accordingly can also receive any form of curve instead of the straight line.

Figs. 10 and 11 finally explain the application of the invention tomulti-coil machines.

I declare that what I claim is 1. In a dynamo-electric machine, anarmature, a field magnet comprising a series of pole pieces of alternatepolarity and each ole piece having a base of considerable ength in adirection corresponding with the direction of rotation of said armatureand the peripheral edges of which pole pieces are inclined and meet atan apex, the tar rangement of said pole pieces being such that eachextends toward the space included between the edges of two other polepieces of opposite polarity, and two successive portions of theperiphery of each of said pole pieces being offset relatively to oneanother and in a direction corresponding with the direction ofrotationof said armature.

2. In a dynamo-electric machine, an armature, a field magnet comprisinga series of pole pieces of alternate polarity and each pole piece havinga base of considerable length in a direction corresponding with thedirection of rotation of said armature and the peripheral edges of whichpole pieces are inclined and meet at an apex which apices extend ast oneanother so that each pole piece of given polarity will lie in betweentwo other pole pieces of opposite polarity, and two successive portionsof the periphery of each of said pole pieces being ofiset relatively toone another and in a direction corin which thev responding with thedirection of rotation of said armature.

3. In a dynamo-electric machine, an armature, a field magnet comprisinga series of pole pieces of alternate polarity and each pole piece havinga base of considerable length in a direction corresponding with thedirection of rotation of said armature and the peripheral edges of whichpole pieces are inclined and meet at an apex which apices extend pastone another so that each pole piece of given polarity will lie inbetween two other pole pieces of opposite polarity, all the bases oflike poles being connected together and to the bases of the poles ofopposite polarity by means of a single magnetic connecting member, andtwo successive portions of the periphery of each of said pole piecesbeing offset relatively to one another and in a direction correspondingwith the direction of rotation of said armature.

4. In a dynamo-electric machine, an armature, a field magnet comprisinga series of pole pieces of alternate polarity and each pole piece havinga base of considerable length in a direction corresponding with thedirection of rotation of said armature and the peripheral edges of whichpole pieces are inclined and meet at an apex which apices extend pastone another so that each pole piece of given polarity will lie inbetween two other pole pieces of opposite polarity, all the basesof'like poles being connected together and to the bases of the poles ofopposite polarity by means of a single magnetic connecting member, andtwo successive portions of the periph cry of each of said pole piecesbeing oil'- set relatively to one another and in a directioncorresponding with the direction of rotation of said armature; and asingle coil for energizing said field magnet.

5. In a dynamo-electric machine, an armature, a field magnet comprisinga series of pole pieces of alternate polarity and each.

pole piece having a base of considerable length in a directioncorresponding with the direction of rotation of said armature and theperipheral edges of which pole pieces are inclined and meet at an apexwhich apices extend past one another so that each pole piece of givenpolarity will lie in between two other pole pieces of opposite polarity,all the bases oflike poles being connectedtogether and to the bases ofthe poles of opposite polarity by means of a single magnetic connectingmember, and two successive portions of the peri hery of each of saidpole pieces being ofl et relatively to one another and in a directioncorresponding with the direction of rotation of said armature, and eachof said pole pieces being provided with a groove extendin parallel withthe axis of said armature an terminating between successive relativelyoifset portions of the periphery of said pole pieces whereby gaps areprovided in said pole pieces. v

6. In a. dynamo electric machine, an armature, a field magnet comprisinga series of pole pieces of alternate polarity and each pole piece havinga base of considerable length a direction corresponding with thedirection of rotation of said armature and the peripheral edges of whichpole pieces are inclined and meet at an apex which apices extend pastcneanother so that each pole piece of given polarity will lie in betweentwo other pole pieces of opposite clarity, all the bases of like polepieces eing connected together and to the bases of the poles of oppositepolarity bymeans of a single magnetic connecting memher, and twosuccessive portions of the peeriphery of each of said pole pieces beingoffset relatively to one another and in a di rection corresponding withthe direction 'of' rotationof said armature, and each of said polepieces being provided with a oove extending parallel with the axis 0said armature and terminating between successiVe relatively ofiisetportions of the periphery of said pole piece whereby gaps are providedin said po e ieces; and a single coil for energizing sai. field magnet.

7. In ad name-electric machine, an armature, and magnet comprising aseries of pole pieces of alternate polarity and each pole piece having abase of considerable ength in a direction corresponding-with themagneticconnecting member, and two successive portions of the periphery of eachof said pole pieces being offset relatively to one another and in adirection corres 0nding with the direction of rotation 0 said armature,and each of said pole pieces being provided with agroove extendingparallel scenes with the axis of said armature and terminating at oneend between successive rela tively offset portions of the 'peripheryofsaid pole pieces and terminating-at the other end short of the bases ofsaid pole pieceswhe-reby gaps are provided in said pole pieces.

8. In a dynamo'electric machine, an armatare, a field magnet comprisinga series of pole pieces of alternate polarity and each pole piece havinga base of considerable length in a direction corresponding with thedirection of rotation of said armature and the peripheral edges of whichpole pieces are inclined and meet at an apex which apices extend pastone another so that each pole piece of given polarity will lie inbetween two other pole pieces of opposite polarity, all-the bases oflike poles being connected, together and to the bases of the poles ofopposite polarity by means of a single magnetic connecting member, andtwo successive portions of the eriphery of each of said pole piecesbeing 0 set relatively to one another and in a direction correspondingwith the direction of rotation of said armatnre, and each of said polepieces being provided with a groove extending parallel with the axis ofsaid armature and terminating at one end between successive relatively011- set portions of the periphery of said pole pieces and terminatingat the other end short of the bases of said pole pieces whereby gaps areprovided in said'polepieces; and a single coil for energizing said fieldmagnet.

9. In a dynamo eleetric machine, an armature provided -with a core madeup of'a plurality of plates bent into helical form, a field magnetsurrounding said armature and provided with a plurality'of poles.ofalternate polarity embracing said armature and disposed inalternation, so that a pole'of given polarity will lie in between twoother poles of opposite polarity, said pole pieces being widest at theirbase and tapering to a narrower free end,

In testimpny whereof I aflix my signature, in presence of two witnesses.

JAKOB SGHUBGH.

WVitnesses:

J EAN GUIDEN,

Hem/I, HAPPE.

